Information Technology Reference
In-Depth Information
1
DP
MC
Simple
0
.
8
0
.
6
0
.
4
0
.
2
0
0
10
20
30
≥
40
τ
(s)
Fig. 4.
Entry time distribution computed using dynamic programming (DP), Monte Carlo (MC),
and the simple (Simple) methods at
t
=17s
computation time. The DP logic using the simple point estimate of
τ
resolves all but one
conflict while rarely reversing or strengthening the advisory, but alerts more frequently
than Monte Carlo.
Ta b l e 4 .
Performance Evaluation
DP Logic (DP Entry)
DP Logic (MC Entry)
Conflicts
2
11
Alerts
540,113
400,457
Strengthenings
39,549
37,975
Reversals
1242
747
DP Logic (Simple Entry)
TCAS Logic
Conflicts
1
101
Alerts
939,745
994,640
Strengthenings
26,485
45,969
Reversals
129
193,582
6.4
Safety Curve
The results of Section 6.3 considered the performance of the system optimized using
the fixed event costs of Table 2. Figure 5 shows the safety curves for the DP logic and
TCAS when different parameters are varied.
The DP logic safety curves were produced by varying the cost of alerting from zero
to one while keeping the other event costs fixed. Separate curves were produced for the
three methods for estimating the entry time distribution. The upper-right region of the
plot corresponds to costs of alerting near zero and the lower-left region corresponds to
costs near one.
